The cause of silicone oil stain
1. Alkalinity
During the pretreatment of cotton fabric, alkali with higher concentration is usually used to remove impurities from the fabric (especially mercerization alkali is used more). It is not easy to clean the alkali when it enters the fiber, and alkali should also be added during dyeing (reactive vat dyes), so the cloth surface may be alkaline during the finishing.
However, chemical fiber fabrics must be restored and cleaned after dyeing. At present, printing and dyeing plants are still using sodium hydrosulfite and caustic soda for cleaning. If they are not cleaned after dyeing, it will also cause alkali on the surface of soft cloth before dyeing. However, ordinary silicone oil is not alkali resistant and will break its emulsion under alkaline conditions, which is the reason why the mill sticks to the roll after passing thousands of meters during the dip rolling process. Therefore, before softening, the alkali agent must be cleaned or acetic acid must be added to the working solution to keep the groove PH5-6.
2. Cohesion
On fabrics containing short fibers (cotton cloth, T/R cloth, velvet), it is inevitable that some of the short fibers will fall down during the processing. The short fibers dropped from the cloth will accumulate in the rolling groove and will cohere with ordinary silicone oil. As the finishing liquid goes up to the roller, it will cohere with the silicone oil extruded and demulsified to form stick rolls or silicon spots. When the water quality is relatively poor, it will also agglomerate with ordinary silicone oil to produce sticky rollers. In addition, similar situations will also exist for fluff fabrics. Do a good job of cleaning before driving, and clean up the spotted hair at any time.
3. Charge stability
Dyes and whitening agents used for cotton cloth are mostly anionic, and cotton whitening is basically completed on the sizing machine. In addition, when the color and luster of dyed cloth are not correct, it is necessary to fine tune the color. Usually, a small amount of dye or paint is added when the softening finishing agent is applied. However, the factory usually uses ordinary silicone oil (weak cation), which will produce an anionic and cationic charge attraction reaction, causing condensation and sticking to the roller. However, the hand softness of the anionic silicone oil does not meet the requirements, causing confusion for the factory. The charge consistency must be considered in processing.
4. Temperature problem
The cloth dyed by the cotton cart must be dried by the drying cylinder, and the large roll is packed or stacked in the cloth box. If it is not sufficiently cooled, especially the large roll cloth, the surface temperature of the fabric may be higher when it is soft, causing the temperature of the grooving working fluid to rise (especially in summer), sometimes to more than 60 ℃, while the heat resistance of ordinary silicone oil is not good, which may also cause roller sticking.
The temperature in the rolling groove shall not exceed 40 ℃.
5. Problem of finalized speed
When the factory is making some thin fabrics, the shaping speed is very fast, sometimes up to 60m/min. The poor permeability of ordinary silicone oil causes the silicone oil to flow back on the roll, causing sticking of the roll. Pay attention to changing the working fluid in the rolling groove and wipe the roll frequently.
6. Cylinder sticking
When many factories are making impregnation softening, ordinary silicone oil will stick to the cylinder wall. After a long time, there will be some black oil spots on the cylinder wall and silicone oil spots on the cloth surface. Strengthen the cleaning work.
7. Hand feeling problem
Due to the increasingly high requirements on the feel of fabrics in the market, and due to different seasons and different customer requirements, various fabrics need to show a variety of different style requirements, such as smooth and drape, smooth and flexible, fluffy and soft, simple elastic, etc. One silicone oil can only reflect one style. As a result, many factories have to use many kinds of silicone oil, resulting in production confusion. Sometimes they can't find silicone oil suitable for customer requirements, so they have to give up business, causing losses. We can select different amino silicone oil terminal groups with different ammonia values to control the molecular weight and molecular distribution to synthesize amino silicone oil with different ammonia value viscosity and reaction to meet the requirements of various fibers in terms of softening, smoothing and elasticity.
8. Cost issues
At present, the most puzzling problem for the printing and dyeing plants is the cost problem. Because the prices of water, electricity and steam are rising, while the printing and dyeing processing fees are decreasing, many printing and dyeing plants have been busy for a year, but their profits are almost non-existent. Therefore, cost control is a problem to be solved by the printing and dyeing plants.
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